The water and carbon footprint of cryptocurrencies and conventional currencies

Abstract

When compared to traditional fiat currencies, cryptocurrencies represent a small, but growing, fraction of financial transactions. The rapid growth of cryptocurrencies has raised concerns regarding the environmental impact of this energy-intensive type of currency. In this study, water and carbon footprints associated with cryptocurrencies are assessed. These environmental footprints are then compared to the water and carbon footprints associated with conventional currencies, which is a novelty of this study. A spatially refined, bottom-up analysis of the most energy-intensive aspects of each financial system is used in the comparison of these systems. Specifically, the energy use for printing money, bank branches, automated teller machines (ATM), and cashless transactions is evaluated at the country level and compared to the energy use of crypto mining around the world. Cryptocurrencies’ electricity use of 236 × 106 megawatt hours (MWh) in 2021 surpassed that of the conventional transaction system, despite cryptocurrencies representing less than 0.5% of global cashless financial transactions. In terms of its water footprint, cryptocurrencies have an annual water consumption of 3670 × 106 cubic meters (m3). Cryptocurrencies' water footprint is more than double that of conventional currencies because crypto mining takes place in countries with higher water intensities for electricity. Crypto mining activities are also estimated to result in almost 139 × 106 tonnes carbon dioxide equivalent (CO2-eq) of global greenhouse gas emissions. While cryptocurrencies represent a small percentage of financial transactions, their environmental impact is much larger than the conventional financial transaction system. This study shows how regulatory changes, such as the 2021 crypto mining ban in China, and crypto mining location can have implications on the environmental footprint associated with cryptocurrency.